Control head with electroluminescent panel in land mobile radio

ABSTRACT

An exemplary land mobile radio control head and method are provided. In one embodiment, the control head has the capability to utilize halo light of the control head to implement a multi-function indicator that communicates a state of the land mobile radio. In another embodiment, the control head has the capability to provide buffer images constructed from data received from the land mobile radio into a video stream for rendering on an electroluminescent display. In another embodiment, the control head provides the capability for a user to modify a configuration stored on the land mobile radio that defines one of several display modes to be utilized in generating data for use in forming images to be rendered on an electroluminescent display.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 120, this application is a continuationapplication claiming priority to U.S. patent application Ser. No.14/989,664, entitled “Control Head With Electroluminescent Panel in LandMobile Radio,” which is a divisional application claiming priority toU.S. patent application Ser. No. 12/614,348, entitled “Control Head withElectroluminescent Panel in Land Mobile Radio,” filed Nov. 6, 2009,which claims the benefit of U.S. Provisional Patent Application Ser. No.61/112,086, entitled “Control Head with Electroluminescent Panel in LandMobile Radio,” filed Nov. 6, 2008, all of which are incorporated hereinby reference for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to the field of land mobileradio and more particularly, but not by way of limitation, to a controlhead having an electroluminescent panel.

BACKGROUND

Land Mobile Radio (LMR) systems are deployed by organizations requiringinstant communication between geographically dispersed and mobilepersonnel. Typical users of LMR systems include police departments, firedepartments, medical personnel, EMS and the military.

SUMMARY

According to an exemplary aspect of the present disclosure, a controlhead for land mobile radio comprises an electroluminescent panel. Asdescribed below, it comprises several aspects capable of enabling one ormore of a multitude of advantages and benefits.

One technical aspect of the exemplary control head may be the capabilityto utilize halo light of the control head to implement a multi-functionindicator that communicates a state of the land mobile radio.

Another aspect may be the capability to buffer images constructed fromdata received from the land mobile radio into a video stream forrendering on an electroluminescent display.

Another aspect may include the capability for a user to modify aconfiguration stored on the land mobile radio that defines one ofseveral display modes to be utilized in generating data for use informing images to be rendered on an electroluminescent display.

Other technical advantages may be readily apparent to one skilled in theart after review of the following figures and description associatedherewith.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following briefdescription, taken in connection with the accompanying drawings anddetailed description, wherein like reference numerals represent likeparts, in which:

FIG. 1 is a perspective view of a control head remote from a land mobileradio.

FIG. 2 is a perspective view of a control head attached to or integratedwith a land mobile radio.

FIG. 3 is a frontal view of an electroluminescent panel of a controlhead.

FIG. 4 is another frontal view of the electroluminescent panel of acontrol head.

FIG. 5 is a view of a display of a control head.

FIG. 6 is a list of symbols that may be used on the display to indicatevarious operating modes and status.

FIG. 7 is a functional block diagram illustrating a land mobile radiosystem implementing a control head.

FIG. 8 is a flow diagram illustrating a method of operation forcontrolling a multi-function indicator implemented utilizing a halolight of a control head.

FIGS. 9A and 9B illustrate an electronic circuit diagram for a controlhead.

FIG. 10 is a perspective view illustrating programming of aconfiguration of a control head utilizing a computer processor.

FIG. 11 is a set of views illustrating results of varying configurationsof a control head to provide different display modes.

FIG. 12 is a screenshot illustrating a user interface component wherebya selection is made for the control head configuration whether toinhibit a zone/channel indicator.

FIG. 13 is a screenshot illustrating a user interface component wherebya selection is made for a control head configuration of a controllerhead type.

FIG. 14 is a screenshot illustrating a user interface component wherebya selection is made for a control head configuration of a display mode.

FIG. 15 is a screenshot illustrating the user interface component ofFIG. 14 whereby another selection is made for the control headconfiguration of a different display mode.

FIG. 16 is a screenshot illustrating a user interface component wherebya selection is made for a control head configuration of display optionsfor the display mode selected in FIG. 14.

FIG. 17 is a screenshot illustrating a user interface component wherebya selection is made for a control head configuration of display optionsfor the display mode selected in FIG. 15.

DETAILED DESCRIPTION

It should be understood at the outset that although exemplaryimplementations of the present disclosure are illustrated below, thepresent disclosure may be implemented using any number of techniques,whether currently known or in existence. The present invention should inno way be limited to the exemplary implementations, options, drawings,and techniques illustrated below, including the exemplary design andimplementation illustrated and described herein. Additionally, thedrawings contained herein are not necessarily drawn to scale.

A component for land mobile radios is a control head that offerssuperior readability and display options for the radio user. Referringto FIG. 1, the control head can be fitted to a remote mount in a landmobile radio installation. Alternatively, referring to FIG. 2, thecontrol head can be fitted or integrated as a dash mount in a landmobile radio installation.

Turning to FIG. 3, the front panel of the control head can have multiplefeatures. For example, it can have an on-off/volume switch 100 forturning the power on/off function to the radio. When the power is on,this control can be rotated to adjust the radio speaker volume. Also, anelectroluminescent display 102 can show all primary operatinginformation, such as active channel, zone, channel/zone alias, statussymbols, and labels for the function buttons under the display. In theembodiment shown in FIG. 3, five buttons are provided under the displayon the control head. Additionally, a multi-function indicator 104 can beprovided in which halo light surrounding a button or switch, such as aselect zone/channel switch 106, is used to indicate radio transmit andreceive status. A steady red halo, in one embodiment, may indicate thatthe radio is transmitting, while a steady green halo may indicate thatthe radio is receiving, and a steady amber halo may indicate that theradio is idle. Further, the select zone/channel switch 106 may beimplemented with two actions: rotation and press. In normal nonmenumode, pressing the control can select either the zone or the channel.Then, rotation of the control can change either the zone or channel. Anindication can be provided on the display whether zone or channel isselected. Yet further, a microphone connection 108 can be provided thatallows a compatible microphone to plug into this jack connector. Furtherstill, the control head can have a number, such as eight, one-touchbuttons 110, including two on the left of the display, five under thedisplay, and an orange button on the right of the display. These buttonsin certain embodiments may be programmed with different radio functions.Finally, a 4-way navigation pad 112 may be provided for navigatingthrough various radio functions and menus. In other embodiments thenavigation pad 112 may be implemented with either more or less than a4-way pad. Like the buttons 110, the pad 112 can be programmed withdifferent radio functions.

Turning now to FIG. 4, as mentioned above, the control head can have anumber, such as nine, of programmable controls 114-130. A number of landmobile radio functions can be assigned to these buttons using a computerprocessor that connects to the land mobile radio control head via themicrophone connection 108. Example radio functions that the user canconfigure include scan, backlight level, monitor, emergency, andtransmitter power.

Referring now to FIG. 5, an advantageous feature of the control head isa highly readable electroluminescent display. In some embodiments, thedisplay is a monochrome display with 320×80 pixels. This display cansupport a Classic Single Line display mode familiar to users of previoustypes of land mobile radio control head displays. In Classic Single Linedisplay mode, the display can have primary fields corresponding to thefields available on earlier model(s) of control heads, but with theaddition of the soft menu keys and display of labels 132 of functionsassigned to those soft menu keys as described above. More familiardisplay contents include channel name 134, zone number 136, channelnumber 138, and symbols 140A-140C to indicate operating mode and status.A list of symbols used on the display to indicate various operatingmodes and status that may be implemented in certain embodiments isprovided in FIG. 6.

The electroluminescent display panel provides a clear, bright andreadable display, which is advantageous in public safety applications.In some embodiments, the electroluminescent display features highbrightness and contrast, resists fading, provides long operating life,has a viewing angle greater than 160°, and provides 200G shockdurability. Furthermore, the electroluminescent display incorporates, insome embodiments, emissive pixel technology, which makes small text morelegible. The electroluminescent display may be operated in a reflectivemode to provide crisp, clear viewing of the electroluminescent displayin bright light, even through polarized lenses. Additionally, the sizeof alphanumeric characters presented on the electroluminescent displaymay be adjusted.

Turning now to FIG. 7, a land mobile radio system 142 generally has acontrol head controller 144 that operates as a slave to a land mobileradio master controller 146. The control head controller 144 detectsuser actuations of controls 148A-148D and signals the master controller146. Controller 144 also reacts to user actuation of a push to talkmicrophone by signaling transmission and passing the audio data.

The master controller 146 transmit audio data from microphone 150 viatransmitter 154, and drive speakers 156 to output audio data receivedvia receiver 158. Also, the master controller 146 constructs userinterface data frame contents of electroluminescent display 160 inaccordance with a configuration stored in data store 152. Additionally,the master controller 146 operates the UI in response to the useractuations at least partly in accordance with the configuration.Controller 144 constructs UI data received from master controller 146into images that are buffered into a video stream for rendering onelectroluminescent display 160.

Additional components of the control head operated by master controller146 in accordance with the configuration include indicators, such aslights or LEDs, located behind light pipes 162A-162E. These light pipesprovide halo light for controls 148A-148D, and for display 160. In oneembodiment, each of the light pipes 162A-162E has an amber LED thatprovides the halo light at an intensity level recorded in theconfiguration, and that can be adjusted by user actuation of one of thecontrols 148A-148D, or another control. At least one of the light pipesadditionally may include red and green LEDs collocated with its amberLED. A signal line 164 to that amber LED can be controlled independentlyof signal lines 166 to the other amber LEDs. The red and green LEDs mayalso have independently controllable signal lines 168 and 170.

Turning now to FIG. 8, the controllers operate the LEDs according to amethod that accomplishes indication of the LMR transmit/receive status.Beginning at power up 172, the configuration is read at step 174 todetermine an intensity level for the amber LEDs, and an active state isset for the amber LEDs at step 176 according to the configuration. Next,one or all inactive amber LEDs may be activated at step 178. Thereafter,the user can adjust intensity of the LEDs by actuation of one of thecontrols of the control head, resulting in modification of theconfiguration according to the user selections at step 180. If the radiois determined to be idle at decision step 182, then processing mayreturn to step 174 and steps 174-182 are traversed continually,resulting in adjustment of the intensity level of the amber LEDsaccording to the user selections.

When the radio is transmitting or receiving, this state change will bedetected at step 182, resulting in deactivation at step 184 of the amberLED that is collocated with the red and green LEDs. Then, if the radiois determined to be transmitting at decision step 186, then the red LED,in one embodiment, is activated at step 188. Thereafter, as long as theradio is determined to still be transmitting at decision step 190, thered LED will remain active. Once a determination is made at step 190that the transmission has ended, then the red LED is deactivated at step192, and processing returns to step 174. Thereafter, the amber LED isreactivated at step 178 and remains active as long as the radio isdetermined to be idle at step 182.

Processing during a receive state similar to that during the transmitstate. If the radio is determined to be receiving at decision step 194,then the green LED, in one embodiment, is activated at step 196, and itremains activated as long as the radio is determined to be receiving atdecision step 198. Once the receipt is determined to have ended at step198, the green LED is deactivated at step 200, and processing returns tostep 174. Thus, a halo light behind one of the user interface componentsserves as a multifunction indicator without interfering with the halofunction of the other components, and while allowing the intensity ofthe amber halo light of the components to be adjusted independently ofthe red and green indicator lights.

Turning now to FIGS. 9A and 9B, the control head display 202, in oneembodiment, can be implemented as an alternating-current thin-filmelectroluminescent (AC-TFEL) display. In this case, the display glasspanel can be covered by two sets of electrodes (80 row electrodes and320 column electrodes) in the horizontal and vertical directions. Theelectrodes are separated by thin film insulating layers. The sensorlayer can be a phosphor layer that emits light when exposed to a strongelectric field. A single light emitting pixel is created at theintersection of each row and column electrode. The brightness of thepixel is determined by the voltage between the two electrodes. In otherembodiments, the control head display 202 may be implemented using otherknown or available display technology.

The control head controller 204, in one embodiment, may be FreescaleMC9S08QE128 which has internal FLASH and SRAM for program and datastorage, general purpose I/O ports, and a UART port for communicationwith the master controller in the land mobile radio. In someembodiments, the control head controller 204 is configured to operate asa slave to the master controller in the land mobile radio for most I/O.In this case, it reports keypresses, switch changes, and microphoneinputs to the master controller via RS485 serial data links. In oneembodiment, the control head controller 204 does not act on these data.Similarly, control of LEDs and other output functions can be directed bythe master controller. In one embodiment, the control head controller204 formats the data, from the master controller, into a pixel imagethat is displayed on the AC-TFEL Display.

The low voltage power supply 206 can be one or more switching and lowdrop out linear regulators which provide power to the logic and analogcircuits. Contained within this plot is a circuit that generates a resetsignal if the battery (13.6 Vdc nominal) supply from the radio, the 3.3Vdc supply, or 1.2 Vdc supply, for example, is out of tolerance.

The high voltage (HV) power supply 208 may be a PWM controlled flybacktransformer design which provide nominal 220 Vdc, 50 Vdc, and −150 Vdcoutputs to power the AC-TFEL Display. Input power to supply may beprovided in one implementation from the radio battery supply (13.6 Vdcnominal) through a FET switch controlled by the Display FPGA 210. Theoutput voltage levels can be adjusted by volume adjustment potentiometer212 to set the brightness level of the AC-TFEL Display. The power supplyswitching frequency (150 kHz) is controlled by Display FPGA 210.

A display frame in one implementation may be composed of 80 lines of 320bits (pixels) for a total of 25600 pixels per frame. In operation, aline of pixels (320) can be shifted into a Column HV Driver/ShiftRegister 216 and latched into output registers which control the outputsof the HV output drivers attached to the column electrodes on theAC-TFEL Display. A new line of pixels is shifted into the register 216after the pixels for the line have been latched into the outputregisters.

When the column data is latched, a HV pulls from the Row HV Driver/ShiftRegister 214 can be applied to the AC-TFEL Display row electrodeassociated with that line of pixels. The HV pulse on the active rowelectrode is either 200 Vdc or −150 Vdc. A pixel will begin to emitlight when the voltage across its row and column electrode exceedsapproximately +/−180 Vdc. For a positive row voltage of pulse of 200Vdc, a column voltage of 0 Vdc will light the pixel and a column voltageof 50 Vdc will turn it off. For a negative row voltage of pulse of −150Vdc, a column voltage of 50 Vdc will light the pixel and a columnvoltage of 0 VDC will turn it off.

The Row HV Driver/Shift Register 214 may be loaded at the beginning ofeach frame, in one embodiment, with a seed bit that enables a single rowHV driver output. After a row is pulsed, the seed bit is shifted to thenext row to enable its HV driver output. The polarity of the row voltagepulse alternates with each line of pixels. The Positive Row VoltageCharge/Discharge FET 218 and Negative Row Voltage Charge/Discharge FET220 circuits generate the HV pulses applied to the row electrode throughthe HV output drivers in the Row HV Driver/Shift Register 214 anddischarge the electrode after the pulse has been applied.

The Display FPGA 210 controls the operation of the circuitry associatedwith the AC-TFEL Display 202 to display images on the display that aregenerated by the control head controller 204. Functionally the DisplayFPGA 210 contains a display data buffer, a frame timing generator, anddisplay control logic to control operation of the Negative Row VoltageCharge/Discharge FET 220, Positive Row Voltage Charge/Discharge FET 218,Row HV Driver/Shift Register 214, and Column HV Driver/Shift Register216.

The display buffer can be a 3200 byte dual port RAM that is accessed bythe control head controller 204 to load pixel data for screen images andby the internal frame generator logic to read the pixel data. Thecontrol head controller can load data into the display buffer through aneight bit parallel data port. Two internal eight bit registers form thebyte address of the display buffer to which the control head controllerwrites data. The control head controller 204 can load an address intothese registers though through the eight bit parallel data port. Thecombined address register can be auto-incremented each time the controlhead controller 204 writes to the display buffer.

The frame timing generator can generate internal frame start, linestart, pixel data, and pixel clock signals that are used by the displaycontrol logic to control the circuitry surrounding the AC-TFEL Display202. The frame refresh rate can be controlled by register that is set bythe control head controller 204 via the eight bit parallel data port.

The display control logic can use the framing, clock, and pixel datafrom the frame timing generator to generate the actual signals used bythe AC-TFEL Display electronics. This signal generation can includetiming for HV row charge/discharge pulses, shifting and latch column androw data, and alternating polarity of row charge/discharge pulses.Additionally, the display control logic can provide for an orderly startup/shut down of the AC-TFEL Display 202 after reset or if the HighVoltage Power Supply 208 is in an under voltage condition.

Turning now to FIG. 10, the display mode of the land mobile radio 222can be programmed by the end user, in one implementation, employing acomputer processor 224 to define a display configuration of the landmobile radio 222. To this end, the computer processor 224 cancommunicate with the land mobile radio 222 by a cable that connects tothe microphone port on the control head. The computer processor 224 runsa program that allows the user to define the configuration stored in aprocessor memory of the radio through a set of menus. By defining thisconfiguration, a number of different display modes can be realized.

Turning to FIG. 11, there are a variety of display modes that can beavailable in some embodiments. For example, a classic mode 226 can beavailable that provides a display mode like that provided by previousland mobile radios not having electroluminescent displays. There canalso be an enhanced single line mode 228 with zone/channel displaysimilar to that of the classic mode, but with soft key function labelsand additional or different symbols or indicating operational modes andstatuses of the radio.

Another display mode 230 can be an enhanced single line mode in whichdisplay of zone and channel is inhibited, permitting display ofadditional text. An additional display mode 232 can be an enhanced dualline display mode allowing display of even more text with zone andchannel display inhibited.

Yet another display mode 234 can be a dual line display mode in whichzone and channel are displayed. Finally, an enhanced menu 236 can bedisplayed with user configurable options that are navigable by use of acontrol on the control head. These modes can be selected by the userselecting options for controller head type, whether to inhibitzone/channel display, a classic versus enhanced display mode, and if inthe enhanced mode, whether to exercise the option to display two linesof text, as indicated below in table 1.

TABLE 1 Inhibit Zone Control Head Chan Display Mode Type IndicatorStandard/ Normal/Lightning Checkbox Enhanced Classic with Zone NormalOff Standard Chan Classic without Zone Normal On Standard Chan EnhancedSingle with Lightning Off Zone/Chan Enhanced Single Lightning On withoutZone Chan Enhanced Dual with Lightning Off Zone/Chan Enhanced DualLightning On without Zone/Chan

There are a number of menus that allow the user to configure the displaymode of the control head in addition to other functions of the radio.For example, turning to FIG. 12, one of the menus that allows the userto make a selection for configuring the display mode can contain acheckbox 238 for exercising an option to inhibit the zone/channelindicator. Selecting this checkbox can inhibit the display of thezone/channel indicator even in the classic mode. Also, turning to FIG.13, a controller type drop down menu 240 can allow the user to selectcontroller type. Turning to FIGS. 14 and 15, a display mode drop downmenu 242 allows the user to select a standard or enhanced display mode,which can affect options provided for configuring the radio. Some ofthese options relate to display options. For example, turning to FIGS.16 and 17, display options 244 for the standard display mode do notpermit selection to display two lines of text. In contrast, the displayoptions 246 in the enhanced mode permit selection to display two linesof text.

Thus, it is apparent that there has been provided, in accordance withthe present disclosure, a control head that satisfies one or more of theadvantages that forth above. Although the preferred embodiment has beendescribed in detail, it should be understood that various changes,substitutions, and alterations can be made herein without departing fromthe scope of the present disclosure, even if all of the advantages andbenefits identified above are not present. For example, the variousembodiments and examples shown in the drawings and descriptions providedherein illustrate that the present disclosure may be implemented andembodied in numerous different ways that still fall within the scope ofthe present disclosure, whether expressly shown herein or not. Forexample, the various elements or components may be combined orintegrated in another system or certain features may not be implemented.Also, the techniques, systems, sub-systems, and methods described andillustrated in the preferred embodiment discrete or separate may becombined or integrated with other systems, designs, techniques, ormethods without departing from the scope of the present disclosure. Forexample, the control head can be used with a wide variety of types ofLMR systems and networks, including those not specifically discussedherein. Other examples of changes, substitutions, and alterations arereadily ascertainable by one skilled in the art and could be madewithout departing from the spirit and scope of the present disclosure.

1. A control head of a land mobile radio, the control head of the landmobile radio comprising: an electroluminescent display showing labelsfor a plurality of function buttons under the electroluminescent displayand a symbol indicating operating status of the land mobile radio; acontrol head controller configured to receive data to construct the datainto one or more images; and a video driver connected to the controlhead controller and buffering the one or more images into a video streamfor rendering on the electroluminescent display, wherein the one or moreimages comprises the labels and the symbol, wherein the one or moreimages comprising the labels is displayed continuously, wherein the oneor more images comprising the symbol is selectably displayed in responseto a change in a state of the land mobile radio, and wherein the controlhead controller is further configured to detect the change in the stateof the land mobile radio and to control activation of the one or moreimages comprising the symbol to indicate the changed state of the landmobile radio.
 2. The control head of claim 1, further comprising: a highvoltage power supply receiving input power from a radio battery supplythrough a FET switch controlled by the video driver, wherein outputvoltage levels are adjustable by a volume adjustment potentiometer toset a brightness level of the electroluminescent display, and whereinpower supply switching frequency is controlled by the video driver. 3.The control head of claim 1, wherein the video driver contains a displaydata buffer, a frame timing generator, and display control logic tocontrol operation of a negative row voltage charge/discharge FET, apositive row voltage charge/discharge FET, a row HV driver/shiftregister, and a column HV driver/shift register.
 4. The control head ofclaim 1, wherein the video driver contains a display data buffer that isa RAM that is accessed by the control head controller to load pixel datafor the one or more images and by internal frame generator logic to readthe pixel data, and the control head controller to load data into thedisplay buffer though a parallel data port.
 5. The control head of claim1, wherein the video driver contains a frame timing generator thatgenerates internal frame start, line start, pixel data, and pixel clocksignals that are used by display control logic to control the circuitryconnected to the electroluminescent display.
 6. The control head ofclaim 1, further comprising: a first LED to provide a first light; and asecond LED to provide a second light, wherein the control headcontroller configured to detect the change in the state of the landmobile radio is further configured to control activation of the firstLED to indicate the changed state of the land mobile radio.
 7. Thecontrol head of claim 6, wherein the control head controller is furtherconfigured to control activation of the second LED to illuminate theelectroluminescent display during an idle state of the land mobileradio.
 8. The control head of claim 7, wherein an intensity of the firstLED is fixed, and an intensity of the second LED is adjustable.
 9. Thecontrol head of claim 1, wherein the first LED and the second LED bothilluminate a first light pipe to illuminate the electroluminescentdisplay.
 10. The control head of claim 1, wherein the first LEDilluminates a first light pipe to illuminate a user actuable button, andwherein the second LED illuminates a second light pipe to illuminate theelectroluminescent display.
 11. A system for configuring a control headof a land mobile radio having an electroluminescent display, the systemcomprising: a computer memory storing a configuration; a controllerconfigured to generate display data according to one of various displaymodes as defined by the configuration; a control head having theelectroluminescent display rendering images formed of the display data,wherein the images comprise labels for a plurality of function buttonsunder the electroluminescent display, wherein the images comprise asymbol indicating operating status of the land mobile radio; a computerprocessor executing a process whereby a user of the computer processorspecifies the display mode to be defined by the configuration; and acontrol head controller to determine the state of the land mobile radio,to detect a change in the state of the land mobile radio, and to controlactivation of the images displayed on the electroluminescent display toindicate the changed state of the land mobile radio and displaying thesymbol indicating operating status of the land mobile radio proximate tothe labels for the plurality of function buttons.
 12. The system ofclaim 11, wherein the computer processor utilizes a menu whereby theuser selects whether to inhibit display of a zone and a channel tomodify the configuration.
 13. The system of claim 11, furthercomprising: a first LED to provide a first light; and a second LED toprovide a second light, wherein the control head controller to detectthe change in the state of the land mobile radio is configured tocontrol activation of the first LED to indicate the changed state of theland mobile radio.
 14. The system of claim 13, wherein the control headcontroller is further configured to control activation of the second LEDto illuminate the electroluminescent display during an idle state of theland mobile radio.
 15. The system of claim 13, wherein an intensity ofthe first LED is fixed, and an intensity of the second LED isadjustable.
 16. The system of claim 13, wherein an intensity of thesecond LED is adjustable via a menu whereby the user selects the displaymode to modify the configuration.
 17. The system of claim 13, whereinthe first LED and the second LED both illuminate a first light pipe toilluminate the electroluminescent display.
 18. A control head of a landmobile radio, the control head of the land mobile radio comprising: aplurality of indicator LEDs comprising at least a first color LED havinga first hue, a second color LED having a second hue, and a third colorLED having a third hue and controllable independently of the first colorLED and independently of the second color LED, a signal line to thethird color LED and connected to a control head controller; and thecontrol head controller configured to determine a state of the landmobile radio as being one of a transmit state, a receive state, or anidle state, wherein the control head controller is further configured todetect the change in the state of the land mobile radio and to controlactivation of the plurality of indicator LEDs to indicate the changedstate of the land mobile radio by illuminating the third color LED thethird hue to indicate the changed state is the idle state, illuminatingthe first color LED a first hue to indicate the changed state is thetransmit state, and illuminating the second color LED a second hue toindicate the changed state is the receive state, and wherein the firsthue comprises a brightness separately controllable by the control headcontroller and different than a brightness of the second hue when thesecond color LED is illuminated and different than a brightness of thethird hue when the third color LED is illuminated.
 19. The control headof claim 18, wherein the brightness the first LED to indicate thechanged state is the idle state is adjustable, and a brightness of thesecond LED to indicate the changed state is the transmit state is fixed.20. The control head of claim 19, wherein the first LED and the secondLED are simultaneously illuminable by the control head controller, andwherein the brightness of the first LED is adjustable via a menu wherebythe user selects a display mode of the control head controller.